The field of the invention is powered skateboards and the invention relates more particularly to electric powered skateboards.
Skateboards are a popular way for young persons to travel. Although there are some gasoline powered skateboards in use, the overwhelming use of skateboards is simply foot power. Electric powered skateboards have been very limited in range and have been hard to control. One such skateboard is shown in U.S. Pat. No. 5,020,621 where a remote controlled unit is used to turn on and off the electric motor which is connected to one of the rear wheels by an O-ring belt. The board has a brake which presses against the rear wheels and may be also controlled by a Bowden cable from the cable connected remote control device. A remote controlled electric skateboard is shown in U.S. Pat. No. 5,330,026 which utilizes an electric motor between two of the wheels of the skateboard. An electric motor is connected to the wheels by sun and planet gear units. An on/off power to the motor is provided by a remote control device. A one-way bearing allows the board to coast when the motor is turned off.
U.S. Pat. No. 5,487,441 shows a motorized skateboard which is controlled by a foot switch. It may be either driven by a drive wheel in the center or the rear wheels may be driven by a drive shaft and gear arrangement. Once again, the motor is provided with an on and off controller.
There are numerous difficulties with these approaches. Because an electric powered skateboard includes both a motor and batteries, it becomes a relatively heavy unit and means must be provided to stop the unit so that it does not constitute a safety hazard to bystanders if the user loses control. While the device of U.S. Pat. No. 5,020,621 has a Bowden cable controlled brake, the use of a cable interferes with the freedom of movement on the board. In the event the user falls off of the board it is very likely that the cable will be pulled out of the unit by the inertia of the board. A motor which is merely turned on causes a substantial battery drain as it starts and also tends to provide a somewhat abrupt start. The result are boards which are limited in range and very difficult to control.